Gnat-Stats, Tiny OLED PC Performance Monitor

Arduino OLED PC Performance Monitor with Client software

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Gnat-Stats, Tiny OLED PC Performance Monitor.

After a recent purchase of a Nvidia GTX1080 graphics card, 4k monitor, plus Doom(2016), I thought it would be great to see some external telemetry..

I then Stumbled upon Psyrax's Hackaday.IO project.

Armed with an Arduino ProMicro and a 128x64 pixel OLED display, I compiled the source code.

The GnatStats Hardware Serial Monitor Visual Studio application is based around Psyrax's "SerialSender" Application , yet heavily modified by Colin Conway.

(Auto Reconnect, CPU/GPU Hardware Name ID's, Frequencies, Serial activity display timeout)

Version 1.32 : Add screen height/width definitions for updated Adafruit SSD1306 library. Arduino UNO/NANO/MICRO ETC. (Atmel ATMega 328 Chips) are not supported, Please don't ask!!!

x-zip-compressed - 14.06 kB - 12/02/2020 at 23:24


TFT Version 1.5. : STM32 BluePill & ProMicro Suppport : 128x160 ST7735 & 240x320 ILI9341 TFT Support : Add PWM Output for Back Light : Separate "Configuration_Settings.h" to make setting up easier

x-zip-compressed - 23.54 kB - 09/12/2020 at 16:06


Gnats Stats PC serial Monitor Program Compiled with .Net 4.6.2 to make use of LibreHardwareMonitor's updated DLL (Fork of OpenHardwareMonitor)

x-zip-compressed - 5.51 MB - 06/04/2020 at 20:01


Add separate "Configuration_Settings.h" to make setting up easier

x-zip-compressed - 17.00 kB - 03/21/2019 at 22:44


Version 1.4 : STM32 BluePill Support : Remove PowerPin Support

x-zip-compressed - 16.67 kB - 03/17/2019 at 18:00


View all 6 files

  • 1 × Arduino ProMicro
  • 1 × SSD1306 or SH1106 OLED Display

  • Run on Startup Win10

    Rupert Hirst06/15/2020 at 22:21 0 comments

    Due to the Windows 10 not allowing programs to run on startup as admin, here is a workaround script.

    1) Right-click on the HardwareSerialMonitor.exe , go to properties, then compatibility and check "Run as Administrator"

    2) Create the VBScript using a text editor (I used Notepad)


      Set WshShell = CreateObject("WScript.Shell" ) 
      WshShell.Run chr(34) & "C:\Program Files (x86)\HardwareSerialMonitor\HardwareSerialMonitor.exe" & Chr(34), 0 
      Set WshShell = Nothing

    (The above path is an example, edit this to where your HardwareSerialMonitor.exe path is located)

    Save the script as "HardwareSerialMonitor.vbs" (no quotes)

    Note: Make sure to save it as a .vbs not .txt

    3) Now place the HardwareSerialMonitor.vbs in the HardwareSerialMonitor folder:

    4) Goto the Windows startup folder

    %AppData%\Microsoft\Windows\Start Menu\Programs\Startup, alternatively access it by Win+R ⇒ shell:startup ⇒ Enter

    Create a shortcut to the .vbs script above by right clicking then "New" ⇒ "Shortcut" ⇒ "Browse" for the "HardwareSerialMonitor.vbs" Script and select it.

    HardwareSerialMonitor Should now run on startup

  • GitHub Links

    Rupert Hirst06/12/2020 at 16:08 0 comments
  • Gnat-Stats TFT Version 1.5

    Rupert Hirst03/21/2019 at 18:49 0 comments

    TFT Version 1.5 

    : STM32 BluePill & ProMicro Suppport
    : 128x160 ST7735 & 240x320 ILI9341 TFT Support
    : Add PWM Output for Back Light
    : Separate "Configuration_Settings.h" to make settings easier

    2.8" ILI9341 240x320  Running on a BluePill STM32.  A bit large maybe to be called Gnat-Stats :)

  • Gnat-Stats OLED Version 1.4

    Rupert Hirst03/17/2019 at 18:06 0 comments

    Gnat-Stats OLED v1.4  

    : STM32 BluePill Support
    : Remove PowerPin Support

    Gnat-Stats small TFT versions coming soon.

  • Hardware Serial Moniitor v1.1

    Rupert Hirst10/16/2018 at 11:29 0 comments

    Hardware Serial Moniitor updated to v1.1

    Compiled with  .Net 4.6.2  to make use of LibreHardwareMonitor's updated  DLL (Fork of OpenHardwareMonitor) 

  • Gnats-Stats Updates

    Rupert Hirst10/16/2018 at 11:26 1 comment

    Version 1.3: 

    Top Config option to disable all pre-selected power/gnd pins on Arduino pins D4 and D5 when not powering OLED from ProMicro 

    Top Config option to disable/enable "activitychecker" (Enable blank screen on serial timeout eg: PC powered down, Disable to retain last sampled info eg: PC crash or overclocking diagnostics) 

    Option to trigger an event at a given CPU or GPU threshold eg: LED indicator at 100% CPU Load. 

    NeoPixel Ring CPU/GPU Bargraph example:


    Custom overlay

View all 6 project logs

  • 1
    Step 1

    Gnatstats Tiny OLED PC performance monitor

    by Rupert Hirst and Colin Conway

    The HardwareSerialMonitor application uses the open source OpenHardwareMonitorLib.dll to sniff the sensors of most modern PC graphics, CPU and motherboards whilst, also pooling windows hardware stats.

    Part of Psyrax's original arduino sketch, is a "anti screen burn" feature. This feature, inverts the screen background (black - white), after a preset time, to give even wear to the OLED display. This feature has been extended to totally turn off the OLED screen when no serial data is available, such as PC power down.

    I wanted to keep the overall footprint as small as possible. The i2C pins on the ProMicro reside on D2(SDA) and D3(SCL). The displays i2c pins lined up but, obviously the power pins would be a problem.

    After measuring a current of 18.6mA on a fully lit OLED display, I decided to pull pin D5 High(5v) and D4 Low(to ground) on the ProMicro to providing the necessary VCC / GND for the display.



    ProMicro Pins: D5(HIGH) D4(LOW) D3 D2


    18mA is within the Atmel 32u4 maximum pin current limit of 20mA. This allowed the display to be simply soldered straight to the header of the ProMicro.

    The HardwareSerialMonitor application is based of Psyrax's original source code and heavily modified by Colin Conway to include additional hardware stats.

View all instructions

Enjoy this project?



archieve.minimadrid wrote 3 days ago point

Hello everyone. First i would like to thank the developers for this nice project. I would love this to keep evolving as its a very nice monitoring setup.

I managed to run the TFT 1.5 version with an Arduino Pro Micro 5V and a 2.8 ILI9341 screen. After properly setting up the pro micro in the Arduino IDE, and flashing the software (prior commenting and uncommenting my hardware in the Configuration.h file) it works as it should. I had to add 2.2K resistors (what i had around) between all pins of screen and Arduino (except VCC, GND and LED pins) because as others commented, the screen does not properly manage 5V signals even if it says so. 

So after wiring the resistors my setup is working nicely! Two things im doubtful:

HardwareSerialMonitor V1.1a its supposed to use Librehardwaremonitor dll library (as it says in the Arduino code) but i think it does not. The DLL incluided is from OpenHardwareMonitor dll, version 0.82. I've manually changed it for the 0.95 version, but for my hardware it does not detect all parameters as it should. Im running a Ryzen 5800X and a RTX3080, so not all data is displayed, for example, cpu temp, and cpu frequency. OpenHardwareMonitor software is not able to fetch this info as its outdated. I would please ask the developers to move the support to the latest LibreHardwareMonitor library, as this one does properly detect the stats and gets updated frequently (OpenHardwareMonitor was forked, and its a dead project now)

- The second thing i would love to be able is to have more screen layouts with better graphics, or at least some documentation to be able to redesign myself, or even better, have different layouts made by the community. That would be awesome. I would love to know how could i add different parameters fetched from the Open/Libre library.

So thanks again, i hope that at least LibreHardwareMonitor library is properly supported soon. Please tell me if you need any help that i can provide. Thanks!

  Are you sure? yes | no

Edgaras wrote 7 days ago point

Hello peeps. Wanted to ask for help. I have succesfully managed to get it test-working with arduino uno (tested with this because I had faulty arduino micro pro), oled shows data with temps model number (ryzen 3600 and rtx 2060) interlaced with blanking lines. Upon some investigation (im not coder, my girl is) we faund out that original adafruit ssd1306 library has default setting for 128x32, so We changed the H file so it would be for 128x64, literally changed just one line of code. It started showing proper screen, correct resolution, but with no data anymore. Any ideas?

  Are you sure? yes | no

dehavok1 wrote 11/09/2020 at 15:50 point

Hi I am not getting any temperature values on a Ryzen 3700X and 5700XT. Any suggestions? Thanks

  Are you sure? yes | no

Cristian Caceres wrote 10/30/2020 at 12:23 point

Hi guys, i have the same issue, a ILI9341 and a Arduino Pro Micro (Atmel Mega 32u4) and only get a White Screen =( please help

  Are you sure? yes | no

ragook wrote 11/10/2020 at 12:15 point

Does the screen work when you use the standard Adafruit graphics test example?

  Are you sure? yes | no

Cristian Caceres wrote 11/10/2020 at 12:34 point

with the adafruit script it does nothing, with the Gnat script it shows only the white screen.

  Are you sure? yes | no

ragook wrote 11/11/2020 at 02:24 point

 If you can't get it working with the basic Adafruit ILI9341 sketch you need to check your wiring and pin assignments. I assume you have  uncommented the correct things in the "Configuration_Settings.h" tab in the gnatstats sketch.

  Are you sure? yes | no

Pogz wrote 10/21/2020 at 09:31 point

Anyone got pin connection with a TFT_ILI9341? Do I need a Logic Level Converter for it? I just get a white screen wiring it directly. 

This is the only one I cant get to work.

  Are you sure? yes | no

ragook wrote 10/21/2020 at 13:59 point

If your MCU is 5v you need a 1.5k resistor  on each of the CS/RST/DC/MOSI/SCLK connections

  Are you sure? yes | no

kyouko wrote 09/22/2020 at 18:18 point

Hi sorry if this question is a bit stupid but i'm new with using arduino's.

I bouth a STM32 (

and an SSD1306 (

my question is what pins do i need to connect because i couldn't really find documentation about these 2 together and they should work.

  Are you sure? yes | no

Pogz wrote 10/21/2020 at 09:29 point

Make sure you have the file GnatStats_ProMicro_STM32_OLED_V1.41_CFG

1.) Check Configuration_Settings.h

2.) Comment out #define ProMicro and uncomment //#define STM32_BluePill

3.) This is  your pinouts: 

- SDA connect to PB7 (B7) 

- SCL(SCK) connect to PB6 (PB7) 

- Ground and VCC pins on its corresponding pins. 

  Are you sure? yes | no

levan wrote 09/21/2020 at 13:06 point

Hello. how can i rotate display? i can not find this line in code? i have ST7735 1.8 inch display.

  Are you sure? yes | no

Pogz wrote 10/21/2020 at 09:18 point

/* Display screen rotation  0, 1, 2 or 3 = (0, 90, 180 or 270 degrees)*/

int ASPECT = 2;

on file Configuration_Settings.h

  Are you sure? yes | no

Tomas wrote 09/20/2020 at 06:32 point

Using HardwareSerialMonitor 1.1 the RAM String is not showing up any value. its R(BLANK)G

  Are you sure? yes | no

Pogz wrote 09/12/2020 at 08:34 point

Can anyone give me a working pin connection with a TFT_ILI9341? I got the TFT_ST7735 but not this bigger TFT_ILI9341? 

My current connection is (following the writeup) 

TFT_ILI9341 - Adruino Pro Micro
CS - 10
RES - RES (set to 0 on source)
DC - 9 
SDI (MOSI) - 16
SCK - 15
LED - 6
SDO (MISO) - 14

but all i get is just a white screen. any tips

  Are you sure? yes | no

ragook wrote 09/12/2020 at 15:58 point

Why do you need a working list when you dont have a ILI9341?

ProMicro SPi= CS:10 RST:0 DC:9 SCLK:15 MOSI:16    MISO isnt needed

Backlight pin is 6

  Are you sure? yes | no

Pogz wrote 09/19/2020 at 07:50 point

i have the ILI9341 .. and im trying to get it to work for it (i have already made it work for ST7735 (as i previously posted) so i dont know what you meant by " you dont have a ILI9341" 

  Are you sure? yes | no

Pogz wrote 09/19/2020 at 08:23 point

FYI, I did follow the pinouts as recommended. But again im just getting a white screen

  Are you sure? yes | no

Pogz wrote 08/30/2020 at 10:23 point

Any solution for the addtional white lines on the display?

Looks like adding an offset should fix? 

  Are you sure? yes | no

RolandoooR1 wrote 09/19/2020 at 20:45 point

I had the same problem. In the Setup ST7735 setup code, comment out the INITR_BLACKTAB and add the INITR_GREENTAB as shown below. This will correct it. 

  /* ST7735 SETUP */
#ifdef TFT_ST7735
  delay(100); // Give the micro time to initiate the SPi bus
  // Use this initializer if you're using a 1.8" TFT
  //tft.initR(INITR_BLACKTAB);   // initialize a ST7735S chip, black tab
  tft.setRotation(ASPECT);// Rotate the display at the start:  0, 1, 2 or 3 = (0, 90, 180 or 270 degrees)

  Are you sure? yes | no

Pogz wrote 08/24/2020 at 12:39 point

Hi, im an absolute Arduino beginner (but I have experiences with the Pi and basic electronic knowledge) and I cant seem to make this work. Below is the board that I used and the OLED I used.


I think I wired it correctly (the OLED had the GND on the 1st pin and the VCC on the 2nd thats why I had to use a wire first to test). SCL and SDA seems to be wired correctly.

On the Arduino side i've done the following: 

1.) Made sure that the Arduino is selected and the correct COM port is selected
2.) Installed the following libraries: Adafruit GFX, Adafruit NeoPixel, Adafruit ST7735
3.) Double clicked on the GnatStats_TFT_ProMicro_STM32_CFG_V1.5.ino and compiled/test. All good. Then uploaded it to the Arduino. No problem.
4.) Ran HardwareSerialMonitor.exe as administrator

But as you see from the photo, I dont get any output. Am I missing something or did I do something wrong? I've also tried directly wiring VCC to the VCC pin of the Arduino and the GND to ground to make sure that its getting enough power but still no dice.

  Are you sure? yes | no

Pogz wrote 08/25/2020 at 10:54 point

ok I was stupid. i was using the TFT version. i though that 1.5 is the latest thus i got that instead. now working with the OLED sketch. 

just a question though, how did you guys power the screen? from the instructions: " D5 High(5v) and D4 Low(to ground) " but its not powering my display. do i need to modify something in the code?

hooking it up to regular vcc and ground line works tho. 

  Are you sure? yes | no

Fizzgig84 wrote 08/31/2020 at 20:42 point

Hey buddy, Im running the exact same everything but still the same issue of nothing showing up. You're running "" ? I feel like I'm missing something.

  Are you sure? yes | no

Pogz wrote 09/02/2020 at 12:34 point

@Fizzgig84 took some wrangling and re-reading due to my inexperience in working with arduino. 

the versioning seems to add to the confusion as people tend to always get the one with the latest version.. 

if you're using something like mine, you need the OLED version (v1.41). 

If you're using the 4 pin OLED, you need to connect (OLED <- > Pro Micro)

SDA - Pin 2
SCK - Pin 3
VCC - VCC 5V rail 
GND - Ground

I was not able to get pins 4 and 5 to word as described in the instruction. I dont get any display light. 

I was able to get the TFT_ST7735 to work too.. but im having trouble on making TFT_ILI9341 work. 

I would probably write a better documentation for those without prior knowledge on Arduino.

  Are you sure? yes | no

Poiaman wrote 07/23/2020 at 12:33 point

Tnks for sharing, i have made the project and its amazing! Now i´m tryng to customize and i need help to understand how can i get the index list of Monitor Serial. For exemple, i would like to make a % for ram use, so i´ll need more information, how the total of memory. Could you help me to understand this part? 

  Are you sure? yes | no

ImmodderNation wrote 06/14/2020 at 23:01 point

How do I add int and strings to the code for voltage and fan speed?

  Are you sure? yes | no

taitelcoms wrote 06/13/2020 at 07:24 point

hello there! I am using ryzen 2700X  but no data for temp and clock speed. CPU Usage working fine. Could you update? I try lastest dll from OpenHardWareMonitor but not working.

  Are you sure? yes | no

Rupert Hirst wrote 06/15/2020 at 22:06 point

are you running the program as admin? that is the usual reason for no CPU frequency or temp. 

HardwareSerialMonitor has always had issues with Ryzen as has openharwaremonitor in the past

  Are you sure? yes | no

taitelcoms wrote 06/16/2020 at 02:08 point

I tried as admin but nothing has changed. Now I commented out frequency and clock then keep waiting if there is any changed ... Thanks. 

  Are you sure? yes | no

Juanillo62gm wrote 05/06/2020 at 03:22 point

Could you compile the code with new OpenHardWareMonitor.dll ? I can't get data from my i9-9900k and RX5700 XT. I'm running OLED_SSD1306 with GnatStats v1.44

  Are you sure? yes | no

Rupert Hirst wrote 06/15/2020 at 22:02 point

I don't  know why its not reading your 9900K , my 9600k works fine 

  Are you sure? yes | no

Psyrax wrote 12/26/2019 at 19:28 point

OMG didn't knew it was forked!!! I'm blushing.

  Are you sure? yes | no

Lautaro wrote 09/06/2019 at 17:37 point

Hi, does anybody have the same problem as I ?

I try to run the compiler and i always get the same error. The error is called ERROR STATUS 1.

Im tring to run the code with an ARDUINO MEGA 2560

Any help please ?

  Are you sure? yes | no

Rupert Hirst wrote 06/15/2020 at 15:20 point

Don't use a MEGA

  Are you sure? yes | no

deemmkka wrote 08/19/2019 at 06:33 point

Help please, does not display CPU temperature i5-8400, although in the program of all shows. Tell me how to fix it?

  Are you sure? yes | no

Ivan wrote 08/06/2019 at 15:18 point

I'm new to Arduino :( someone can explain to me, if it is enough to move the files I find here or I have to do something else

Thank you in advance guys

  Are you sure? yes | no

adamnemeth0 wrote 07/23/2019 at 07:44 point

Hi, does anybody have the same problem as I ?

I am running this on a ryzen cpu and I got no temps. When I modified the hwmonitor 1.0 to look for different name for temps it was working.

But the hwmonitor 1.0 using openhardware monitor lib which is not showing correct cpu speeds. So I would like to use the Hwmonitor 1.1 with the librehardware lib. But I have the same issue that I have no temp readings, and the source code is password protected so I can't make the same modification as it was on the hwmonitor 1.0

Could anybody tell me how to make the Hwmonitor 1.0 using librehardware lib. Or send me the source for the Hw 1.1. ?

  Are you sure? yes | no

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